A new study says it has ended the long-lasting debate on the causes of dyslexia and also opened the way to a new approach for early identification and interventions for the 10 percent of children for whom reading is extremely difficult.

For children with dyslexia, the trouble begins even before they start reading and for reasons that don't necessarily reflect other language skills. Researchers say their new report reveals a causal connection between early problems with visual attention and a later diagnosis of dyslexia.

The researchers studied Italian-speaking children for a period of three years, from the time they were prereading kindergarteners until they entered second grade. Andrea Facoetti of the University of Padua in Italy, and a team including Sandro Franceschini, Simone Gori, Milena Ruffino, and Katia Pedrolli, assessed prereaders for visual spatial attention—the ability to filter relevant versus irrelevant information—through tests that asked them to pick out specific symbols amid distractions. The children also took tests on syllable identification, verbal short-term memory, and rapid color naming, followed over the next two years by measures of reading. Those test results showed that kids who initially had trouble with visual attention were also the ones to later struggle in reading.

"Visual attention deficits are surprisingly way more predictive of future reading disorders than are language abilities at the prereading stage," said Facoetti. "This is a radical change to the theoretical framework explaining dyslexia. It forces us to rewrite what is known about the disorder and to change rehabilitation treatments in order to reduce its impact."

He says that simple visual-attention tasks should improve the early identification of children at risk for dyslexia. "Because recent studies show that specific prereading programs can improve reading abilities, children at risk for dyslexia could be treated with preventive remediation programs of visual spatial attention before they learn to read."